MAHARASHTRA STATE BOARD OF TECHNICAL EDUCATION … · choose your correct model as per the...

MAHARASHTRA STATE BOARD OF TECHNICAL EDUCATION

(Autonomous)

(ISO/IEC - 27001 - 2005 Certified)

WINTER – 2016 EXAMINATION

Model Answer Subject Code:

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Important Instructions to examiners:

1) The answers should be examined by key words and not as word-to-word as given in the model

answer scheme.

2) The model answer and the answer written by candidate may vary but the examiner may try to

assess the understanding level of the candidate.

3) The language errors such as grammatical, spelling errors should not be given more Importance

(Not applicable for subject English and Communication Skills).

4) While assessing figures, examiner may give credit for principal components indicated in the

figure. The figures drawn by candidate and model answer may vary. The examiner may give

credit for any equivalent figure drawn.

5) Credits may be given step wise for numerical problems. In some cases, the assumed constant

values may vary and there may be some difference in the candidate‟s answers and model

answer.

6) In case of some questions credit may be given by judgement on part of examiner of relevant

answer based on candidate‟s understanding.

7) For programming language papers, credit may be given to any other program based on

equivalent concept.

Q.N

o.

Sub

Q.N.

Answer Marking

Scheme

1.

a)

Ans.

Attempt any FIVE of the following:

Give three models of OO methodology.

Three models of OO methodology:

1. Class Model

2. State Model

3. Interaction Model

1. Class Model:

The class model describes the structure of objects in a system, their

identity, their relationships to other objects, their attributes and their

operations. The class model provides context for the state and

interaction models.

2. State Model:

The state model describes those aspects of objects concerned with

time and the sequencing of operations also events that mark changes,

states that define the context for the events, and the organization of

events and states. The state model captures control, the aspect of a

system that describes the sequences of operations that occur, without

regard for what the operations do, what they operate on, or how they

are implemented.

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models

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3. Interaction Model:

The interaction model describes interaction between objects i.e. how

individual objects collaborate to achieve the behavior of the system

as a whole. The state and interaction models describe different

aspects of behavior. Use cases, sequence diagrams and activity

diagrams document the interaction model. Use cases document

major themes for interaction between the system and outside actors.

b)

Ans. Give the use of generalization in class modeling.

Use of generalization in class modeling:

1. Generalization supports for polymorphism. In this, a call for an

operation at the superclass level is resolved by the object oriented

compiler to the method that matches the calling object‟s class.

Polymorphism increases the flexibility of software.

2.

3. Generalization structures the description of objects. When

generalization is used objects are organizes on the basis of their

similarities and differences.

4.

5. Generalization is used to reuse the existing code. Reuse is more

productive than repeatedly writing a code from scratch.

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c)

Ans. Explain the notations used in use case diagrams.

Notations used in use case diagram are:

1. 1. Use case:

Use case is the description of set of sequences of actions. It is

graphically represented as an ellipse and labeled with the name of the

use case. Use case represents an action performed by a system.

Notation:

2. 2. Actor:

An actor represents a coherent set of roles that users of use case can

play while interacting with use cases. An actor represents a role that a

human, hardware device or another system plays when it

communicates with the system.

It is represented with the following notation.

Notation:

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3. 3. Association:

An association is a connection between an actor and use case. It

indicates that both are communicating with each other. Association is

represented with a solid line.

Notation:

4. 4. Generalization:

Generalization is used to show the relationship between two use

cases. In this relationship the child use case inherits the behavior and

meaning of parent use case. It is represented with the solid line with a

large hollow triangle as an arrowhead. Arrow head indicates direction

of generalization.

Notation:

5. 5. Include Relationship:

An include relationship is the directed relationship between two use

cases. Including a use case requires forceful execution of included

use case.

Notation/example:

6. 6. Extend Relationship:

It is a directed relationship between two use cases that specifies extra

actions in a system. Extend relationship specifies optional behavior

for extending use case.

Notation/example:

Pin change User Login

<<extend>>


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d)

Ans.

Draw the state chart diagram for ATM.

(Any other relevant diagram shall be considered)

State chart diagram for ATM:

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State

chart

diagram

for ATM

with

correct

logic

and

notation

s

4M

e)

Ans. Explain how nodes communicate in deployment diagram.

Communication of nodes in deployment diagram:

1. 1. Communication paths are used to show that nodes communicate

with each other at runtime. A communication path is drawn as a solid

line connecting two nodes. The type of communication is shown by

adding a stereotype to the path.

2. 2. Communication paths show that the nodes are capable of

communicating with each other and are not intended to show

individual messages.

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correct

explanat

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Example 1:

A desktop PC and server communicate via TCP/IP

Example 2:

Communication paths between execution environment nodes

in

deploym

ent

diagram

4M

f)

Ans.

Draw the deployment diagram for login form

(Any other relevant deployment diagram for login form of any

system shall be considered).

4M

Deploym

ent

diagram

for login

form

with

correct

logic

and

notation

s 4M

2.

a)

Ans.

Attempt any TWO of the following:

Explain the concept of metadata and constraints on object.

Metadata:

Metadata is data that describes other data. For example, the definition

of a class is metadata. Models are inherently metadata, since they

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describe the things being modeled. Relational database management

system use metadata. A person can define database tables for storing

information.

Example:

Each car model has its own attributes and associations. Each car

model object also describes a set of physical cars owned by persons.

Each car receives the common attributes from car model but also

own list of particular attributes such as serial number, color and a list

of options. Car Model object as a pattern, a piece of metadata, that

describes car objects.

Constraints on Object: 1. 1. Constraint is a boolean condition involving model elements such

as objects, classes, attributes, links and associations.

2. 2. A constraint restricts the values that entities/elements can assume.

3. 3. Constraints can be expressed with natural language or a formal

language such as the object constraint language. (OCL).

4. 4. The structure of model expresses many constraints but sometimes

it is helpful to add explicit constraints.

Examples of some constraints are:

No employee‟s salary can exceed the salary of employee‟s boss

No window can have an aspect ratio of less than 0.8 or greater

than 1.5.

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Explana

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Constrai

nts on

object

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The priority of job may not increase

b)

Ans.

Draw the use case diagram for railway reservations system.

(Any other relevant diagram shall be considered)

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Use case

diagram

for

railway

reservati

on

system

with

correct

logic

and

notation

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NewActivity

NewActivity2NewActivity3

Activity

Activity 1 Activity2

c)

Ans. Explain the concept of join and fork with example.

Join in Activity diagram: 1. A join in Activity diagram represents the synchronization of two or

more concurrent flows of control.

2. A join may have two or more incoming transitions and one

outgoing transition.

3. Above the join, activities associated with each of these paths

continue in parallel.

4. At the join, the concurrent flows synchronize, means each waits

until all incoming flows have reached at the join, at which point one

flow of control continues on below the join.

Notation:

Fork in Activity diagram: 1. 1. A fork in activity diagram represents the splitting of a single flow

of control into two or more concurrent flows of control.

2. 2. A fork may have one incoming transition and two or more

outgoing transitions, each of which represents an independent flow of

control.

3. 3. Below the fork, the activities associated with each of these paths

continue in parallel.

Notation:

Example:

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Join -

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In the above example there are two forks and two joins. Joins and

forks should balance, meaning that the number of flows that leave a

fork should match the number of flows that enter its corresponding

join. The activity Stream audio needed to tell the activity Synch

mouth when important pauses and intonations occurred. Similarly, for

Synch mouth, we would see transitions triggered by these same

signals, to which the Synch mouth state machine would respond.

Any

relevant

example

of join

and fork

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3.

a)

Ans.

Attempt any FOUR of the following:

Explain the principles of modelling.

Modelling principles are as follows:

1. 1. “The choice of what models to create has a profound influence on

how a problem is attacked and how a solution is shaped”. This means

choose your correct model as per the requirement of problem

statement. Wrong model will mislead you, causing to focus on

irrelevant issues.

2. “Every model may be expressed at different levels of precision:”

This means all the user and developers both may visualize a system at

different levels of details at different time.

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3. “The best models are connected to reality”.

4. “No single model is sufficient. Every nontrivial system is best

approached through a small set of nearly independent models:” This

means you need to have use case view, design view, process view,

implementation view and development view. Each of these

views may have structural as well as behavioral aspects. Together

these views represent a system.

b)

Ans.

Explain how to create objects and classes.

(Any Relevant explanation shall be considered)

The following steps are performed to create Objects and classes.

1. Identify Objects and Classes

From the detail statement of the problem, identify objects and

classes as below:

a. Physical entities such as houses, machines etc.

b. Nouns such as tickets, systems etc.

c. Materials such as books, records etc.

d. Roles such as teacher, student, customer etc.

e. Events such as interrupt, request, copying etc.

2. Prepare a data dictionary

3. Identify Associations.

4. Identify attributes of objects and links.

5. Organize and simplify object classes using inheritance.

6. Identify operations to be included in a class.

7. Verify that access paths exist for likely queries.

8. Iterate and refine the model.

9. Group classes into models.

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c)

Ans. How to create and destroy messages in sequence diagram?

Create message:

1. Objects can be created according to the requirement of the system

in between the processing of the system because they are not

required for the entire duration of the sequence diagrams interaction.

2. If an object does not exist at the beginning of a sequence diagram

then it must be created in the system.

3. The UML shows creation by placing the object notation at the

head of the arrow for the message call that creates an object.

Destroy message:

1. An object can destroy itself or it can be destroyed by other objects

of the sequence diagram because those objects may not further

require during the system.

2. If the object is destroyed by itself then “X” is placed at the head

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create

message

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message

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of the call arrow that destroys the object.

3. If the object destroys and returns control to another object then

“X” is placed at the tail of the return arrow. Example:

d)

Ans.

Draw the activity diagram for hospital management system.

(Any Relevant diagram shall be considered)

4M

Activity

Diagram

for

Hospital

manage

ment

system

with

correct

logic and

notation

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e)

Ans. Explain the notations used in state diagram.

State chart diagram notations:

Sr

.

N

o.

Name Symbol Description

1 State

A state is a condition or a situation in

the life of an object during which it

satisfies some conditions, performs

some activity or waits for some

events. It is represented with a

rounded rectangle. Name of the state

is written inside the rectangle.

2 Initial

State

It indicates the default starting place

of the state chart diagram. An initial

state is represented as filled circle.

3 Final

State

Final state indicates end of the

execution of the system. It is

represented as a filled black circle

surrounded by an unfilled circle.

4 Transit

ion

A transition is a relationship between

two states. It indicates that an object

in the first state performs some action

and enters in the second state when a

specific event occurs. Transition is

represented with a directed line.

5 Event

An event is the specification of a

significant occurrence that has

location in time and space. An event

can be a signal or a call to a function.

An event is indicated with text

written above or below transition line.

6 Action

An action is an executable

computation. Action may include

operation calls, the creation and

destruction of another object or

sending of a signal to an object. It is

indicated with text written below or

above the transition line associated

with an event separated by slash.

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f) Draw the component diagram for customer login for railway 4M


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Ans.

reservation form.


compon

ent

diagram

of

custome

r login

for

railway

reservati

on form

with

correct

logic

and

notation

s 4M

4.

a)

Ans.


Give propogation of operations.

1. Propagation is also called as triggering.

2. It is the automatic application of an operation to a network of

objects when the operation is applied to some starting object.

3. As moving aggregate moves its parts, the move operation

propagates to the parts.

4. Propagation of operations to parts is good indicator of aggregation.

The concept of propagation of operations provides a concise and

powerful way for specifying a continuum of behavior.

Propagation is possible for other operations including save/restore,

destroy, print, lock and display.

Example/diagram:

Above diagram shows an example of propagation. A person owns

multiple documents. Each document consists of paragraph that in turn

consists of characters. The copy operation propagates from

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documents to paragraphs to characters. Copying a paragraph copies

all the characters in it. The operation does not propagate in the

reverse direction. A paragraph can be copied without copying the

whole document. Copying a document copies the owner link but does

not spawn a copy of the person who is owner.

b)

Ans.

Draw use case diagram for hotel management system.


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Use case

diagram

for

Hotel

Manage

ment

System

with

correct

logic

and

notation

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c)

Ans.

Explain how multiple tasks are performed in swim lane diagram.

(Any Relevant explanation shall be considered)

Activity diagrams provide an ability to clarify which actor performs

which activity. A swim lane diagram (also sometime called a cross-

functional diagram) documents the steps or activities of a process

flow or workflow. More specifically, a swim lane diagram groups

these activities into swim lanes which are horizontal or vertical

columns that contain all of the activities which fit into the category

represented by that swim lane.

Swim lanes can represent many categories of information such as

actors which perform the activities (i.e., role or department), the stage

of the process in which the activity takes place, or whatever else the

creator of the document feels should be emphasized and

communicated by the swim lane diagram. The term swim lane was

adopted due to the visual similarity between the horizontal rows of

the diagram to that of the swim lanes found within a swimming pool.

1. Swim lane diagrams are used for information flows that involve

different separate entities that are not necessarily working in a

linear sequence.

2. It is used for administrative processes as, for example, order

processing, part development, marketing, etc.

3. Each lane represents a different entity. An entity is usually

associated with a certain function.

4. Hence, it could be a department, a subgroup of a department, an

office, individual people, or it could even be larger than a

department as, for example, a plant, a site, the customer, or the

suppliers.

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Example

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5.

a)

Ans.

Attempt any FOUR of the following:

Explain the UML architecture.

System architecture contains five views:

1. Use case view: - it describes the use case that shows the behavior

of the system as seen by its end users, analysts and testers. The

static aspect of this view is shown in use case diagram.

2. Design view: - it consists of classes, interfaces and collaborations

required for the system. It supports the functional requirements of

the system. It specifies services that the system provides to its end

user. The static aspect is shown in class diagram and object

diagram.

3. Process view:-it focuses on threads and processes that form the

system‟s concurrency and synchronization mechanism. It

addresses the performance, scalability and throughput of the

system. Static aspect is shown in class and object diagram.

4. Implementation view:-it focuses on the components and files that

are used to assemble and release the physical system. It addresses

configuration management of the system‟s releases. The static

aspect of this view is shown in component diagram.

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5. Deployment view: - it specifies the nodes that form the system‟s

hardware topology on which the system executes. It addresses the

distribution, delivery and installation of the parts that make up the

physical system. The static aspect of this view is shown in

deployment diagram.

Diagram

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b)

Ans. Explain the concept of values and attributes.

Value: - A value is a piece of data.

Attributes: - An attributes is a named property of a class that

describes a value held by each object of the class.

A class may have any number of attributes or no attributes at all.

An attribute represents some property of the thing that is shared by all

the objects of that class.

Each attribute name is Unique within a class. Each attribute has a

value for each object. For example, attribute Name can have value as

„abc‟ for one object and „xyz‟ for other object.

Attributes are listed in the second part of Class Box. Each attribute

name may be followed by data type of the value and optional default

value. A colon precedes the type and equal to sign precedes the

default value.

For Example: Class Person has attributes Name, Birthdate and

weight. Name is string, Birthdate is Date and Weight is integer.

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c)

Ans. Explain system boundries for use case diagram.

System boundary specifies the scope of an application in order to

specify functionality. It indicates what the system includes and what

it omits.

System boundary groups together logically related things. It separates

use cases and actors involved in the system.

System boundary is shown with a box in a use case diagram.

Example:

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d)

Ans. Explain actions and activity node concept in activity diagram.

Action node/state: The executable, atomic computations such as

sending a signal to an object, creating or destroying object are called

as action states. Action states cannot be decomposed. For example: an

expression for calculating gross salary, entering amount for

withdrawal cannot be decomposed.

Example:- Action state

Activity node/state: an activity is an ongoing non-atomic execution

within an activity diagram. Activity results in action. Activity states

can be further decomposed in multiple activities. Activity states are

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not atomic that means they may be interrupted and they may take

some time duration to complete. Activity state is a composite of flow

control made up of other activity states and action states.

Example:-Activity state

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activity

node/sta

te 2M

e)

Ans. Explain composite state diagram.

Composite state is defined as state that has sub states. A Sub state

can be sequential or concurrent. Sequential sub states include states of

things that change with the help of transition in a particular sequence.

Concurrent sub states are the states that executes in parallel. They are

independent of each other. In nested state diagram, each of nested

state receives the outgoing transition of its composite states.

Example:-

The above state diagram shows automatic transition with composite

state. Automatic transition can be done in reverse, neutral or forward

direction. If it is in forward then it can be in first, second or third

gear. The first, second and third are nested states for a composite state

forward. Selecting N in any forward gear shifts a transition from

forward to neutral. Select F in neutral state causes a transition to

forward state. The nested state first is the default initial state.

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f)

Ans. Explain node instances of deployment diagram with example.

A node is a physical element that exists at run time and represents a

computational resource with some memory and processing capability.

Instance of node can be hardware device or execution environment.

Hardware device can be server, printer etc.

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Example:

Execution environment can be a node that offers an execution

environment for specific types of components that are deployed on

it in the form of executable.

Example:

Example

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6.

a)

Ans.


Give the importance of modelling in Rambaugh model.

Modeling is a central part of all activities that lead up to the

deployment of good software. It is required to build quality software.

Importance of Modeling:

Modeling gives graphical representation of system to be built.

Modeling contributes to a successful software organization.

Modeling is a proven and well accepted engineering technique.

Modeling is not just a part of the building industry. It would be

inconceivable to deploy a new aircraft or an automobile without

first building models-from computer models to physical wind

tunnels models to full scale prototypes.

A model is a simplification of reality. A model provides the

blueprint of a system.

A model may be structural, emphasizing the organization of the

system, or it may be behavioral, emphasizing the dynamics of the

system.

Models are build for better understanding of the system that we

are developing:

a. Models help us to visualize a system as it is or as we want it to

be.

b. Models permit us to specify the structure or behavior of a

system.

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c. Models give us a template that guides us in constructing a

system.

d. Models support the decisions we have made.

Modelling principles are as follows:

2. 1. “The choice of what models to create has a profound influence on

how a problem is attacked and how a solution is shaped”. This means

choose your correct model as per the requirement of problem

statement. Wrong model will mislead you, causing to focus on

irrelevant issues.

3.

2. “Every model may be expressed at different levels of precision:”

This means all the user and developers both may visualize a system at

different levels of details at different time.

3. “The best models are connected to reality”.

4. “No single model is sufficient. Every nontrivial system is best

approached through a small set of nearly independent models:” This

means you need to have use case view, design view, process view,

implementation view and development view. Each of these

views may have structural as well as behavioral aspects. Together

these views represent a system.

b)

Ans. Differentiate between aggregation and association.

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Compar

ative

descripti

on of

aggregat

ion-

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ciation-

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c)

Ans. Explain loop control in sequence diagram.

Loop is used to show repetitive execution of interactions. Loop

fragment operator is used inside fragment box to indicate recursive

application. Loop can be controlled either with iterations or with a

guard condition. Loop operator can have values for lower bound and

upper bound. When loop operator does not contain bounds it indicates

that the interaction execute with zero as lower bound and infinite

upper bound.

Example:-

1. In the sequence diagram below, the loop has no bound specified

with operator. So lower bound of the loop is 0 and upper bound is

infinite.

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loop

control

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Loop

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2. The operator in the below sequence diagram has only one value so

loop will be executed exactly the specified number of times i.e. 10.

3. In the below sequence diagram, the loop contains lower bound as

well as upper bound value so the loop will execute six number of

times.

Explana

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loop

with one

bound

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Explana

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loop

with two

bounds

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